Subsurface structural mapping of the Ba Na area (Vietnam) utilizing aeromagnetic data

Abstract

The Ba Na region plays a crucial role in deciphering the tectonic evolution of the Indochina terrane. This study addresses the scarcity of geophysical research in the area by utilizing aeromagnetic data to delineate subsurface structures. Various techniques including reduction to the pole (RTP), multi-stage RTP, reduction to the equator (RTE), enhanced analytic signal (EAS), theta map (TM), tilt angle of the horizontal gradient (TAHG), and fast sigmoid-based edge detection (FSED) were examined on synthetic datasets before employing them to analyze the geomagnetic field of the region. The results from the synthetic example show that the use of the RTE filter can provide a more reliable and accurate approach for removing asymmetries caused by non-vertical magnetization. These results also demonstrate the efficacy of applying TAHG and FSED to RTE aeromagnetic data for mapping subsurface structures in the Ba Na area. The findings reveal major magnetic contacts in the approximate ENE-WSW direction and the secondary contacts in the N-S direction, with depths ranging from 200 to 650 m, possibly arising from the collision between the Northern and Southern Vietnam blocks. Additionally, intrusive structures were identified in the region. This study constitutes the initial magnetic interpretation, providing valuable insights into the structural characteristics of the Ba Na area and filling a notable research gap in the understanding of this geologically significant region.